Microtubule-targeting agents (MTAs) constitute a diverse group of chemical compounds that bind to microtubules and affect their properties and function. Disruption of microtubules induces various cellular responses often leading to cell cycle arrest or cell death, the most common effect of MTAs. MTAs have found a plethora of practical applications in weed control, as fungicides and antiparasitics, and particularly in cancer treatment. Here we summarize the current knowledge of MTAs, the mechanisms of action and their role in cancer treatment. We further outline the potential use of MTAs in anti-metastatic therapy based on inhibition of cancer cell migration and invasiveness. The two main problems associated with cancer therapy by MTAs are high systemic toxicity and development of resistance. Toxic side effects of MTAs can be, at least partly, eliminated by conjugation of the drugs with various carriers. Moreover, some of the novel MTAs overcome the resistance mediated by both multidrug resistance transporters as well as overexpression of specific β-tubulin types. In anti-metastatic therapy, MTAs should be combined with other drugs to target all modes of cancer cell invasion.

• MeSH
• lidé MeSH
• mikrotubuly účinky léků   MeSH
• nádory farmakoterapie   MeSH
• protinádorové látky farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

• Publikační typ
• abstrakt z konference MeSH

BACKGROUND: Hypoxia is a prominent feature of solid tumors, dramatically remodeling microtubule structures and cellular pathways and contributing to paclitaxel resistance. Peloruside A (PLA), a microtubule-targeting agent, has shown promising anti-tumor effects in preclinical studies. Although it has a similar mode of action to paclitaxel, it binds to a distinct site on β-tubulin that differs from the classical taxane site. In this study, we examined the unexplored effects of PLA in hypoxia-conditioned colorectal HCT116 cancer cells. METHODS: Cytotoxicity of PLA was determined by cell proliferation assay. The effects of a pre-exposure to hypoxia on PLA-induced cell cycle alterations and apoptosis were examined by flow cytometry, time-lapse imaging, and western blot analysis of selected markers. The hypoxia effect on stabilization of microtubules by PLA was monitored by an intracellular tubulin polymerization assay. RESULTS: Our findings show that the cytotoxicity of PLA is not altered in hypoxia-conditioned cells compared to paclitaxel and vincristine. Furthermore, hypoxia does not alter PLA-induced microtubule stabilization nor the multinucleation of cells. PLA causes cyclin B1 and G2/M accumulation followed by apoptosis. CONCLUSIONS: The cellular and molecular effects of PLA have been determined in normoxic conditions, but there are no reports of PLA effects in hypoxic cells. Our findings reveal that hypoxia preconditioning does not alter the sensitivity of HCT116 to PLA. GENERAL SIGNIFICANCE: These data report on the cellular and molecular effects of PLA in hypoxia-conditioned cells for the first time, and will encourage further exploration of PLA as a promising anti-tumor agent.

• MeSH
• apoptóza účinky léků   MeSH
• bicyklické sloučeniny heterocyklické farmakologie   MeSH
• buňky HT-29 MeSH
• cyklin B1 metabolismus   MeSH
• HCT116 buňky MeSH
• hypoxie buňky * MeSH
• kontrolní body buněčného cyklu účinky léků   MeSH
• laktony farmakologie   MeSH
• lidé MeSH
• mikrotubuly účinky léků   MeSH
• paclitaxel farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• protinádorové látky farmakologie   MeSH
• vinkristin farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: We investigated the targeting of microtubules (MT) and F-actin cytoskeleton (AC) of the human pathogenic yeast Cryptococcus neoformans with agents for cancer therapy, in order to examine whether this yeast cytoskeleton could become a new antifungal target for the inhibition of cell division. METHODS: Cells treated with 10 cytoskeleton inhibitors in yeast extract peptone dextrose medium were investigated by phase-contrast and fluorescence microscopy, and growth inhibition was estimated by cell counts using a Bürker chamber and measuring absorbance for 6 days. RESULTS: Docetaxel, paclitaxel, vinblastine sulfate salt, cytochalasin D and chlorpropham [isopropyl N-(3-chlorophenyl) carbamate] did not inhibit proliferation. The MT inhibitors methyl benzimidazole-2-ylcarbamate (BCM), nocodazole, thiabendazole (TBZ) and vincristine (VINC) disrupted MT and inhibited mitoses, but anucleated buds emerged on cells that increased in size, vacuolated and seemed to die after 2 days. The response of the cells to the presence of the actin inhibitor latrunculin A (LA) included the disappearance of actin patches, actin cables and actin rings; this arrested budding and cell division. However, in 3-4 days, resistant budding cells appeared in all 5 inhibitors. Disruption of the MT and AC and inhibition of cell division and budding persisted only when the MT and AC inhibitors were combined, i.e. VINC + LA, BCM + LA or TBZ + LA. CONCLUSION: The MT and AC of C. neoformans are new antifungal targets for the persistent inhibition of cell division by combined F-actin and MT inhibitors.

• MeSH
• aktiny antagonisté a inhibitory   MeSH
• antifungální látky farmakologie   MeSH
• bicyklické sloučeniny heterocyklické farmakologie   MeSH
• buněčné dělení účinky léků   MeSH
• Cryptococcus neoformans účinky léků   MeSH
• fluorescenční mikroskopie MeSH
• lidé MeSH
• mikrofilamenta účinky léků   MeSH
• mikrotubuly účinky léků   MeSH
• protinádorové látky farmakologie   MeSH
• racionální návrh léčiv MeSH
• thiazolidiny farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Major advances in the genomics and epigenomics of diffuse gliomas and glioblastoma to date have not been translated into effective therapy, necessitating pursuit of alternative treatment approaches for these therapeutically challenging tumors. Current knowledge of microtubules in cancer and the development of new microtubule-based treatment strategies for high-grade gliomas are the topic in this review article. Discussed are cellular, molecular, and pharmacologic aspects of the microtubule cytoskeleton underlying mitosis and interactions with other cellular partners involved in cell cycle progression, directional cell migration, and tumor invasion. Special focus is placed on (1) the aberrant overexpression of βIII-tubulin, a survival factor associated with hypoxic tumor microenvironment and dynamic instability of microtubules; (2) the ectopic overexpression of γ-tubulin, which in addition to its conventional role as a microtubule-nucleating protein has recently emerged as a transcription factor interacting with oncogenes and kinases; (3) the microtubule-severing ATPase spastin and its emerging role in cell motility of glioblastoma cells; and (4) the modulating role of posttranslational modifications of tubulin in the context of interaction of microtubules with motor proteins. Specific antineoplastic strategies discussed include downregulation of targeted molecules aimed at achieving a sensitization effect on currently used mainstay therapies. The potential role of new classes of tubulin-binding agents and ATPase inhibitors is also examined. Understanding the cellular and molecular mechanisms underpinning the distinct behaviors of microtubules in glioma tumorigenesis and drug resistance is key to the discovery of novel molecular targets that will fundamentally change the prognostic outlook of patients with diffuse high-grade gliomas.

• MeSH
• gliom farmakoterapie   genetika   metabolismus   MeSH
• karcinogeneze účinky léků   genetika   metabolismus   MeSH
• lidé MeSH
• mikrotubuly účinky léků   genetika   metabolismus   MeSH
• neuronové sítě MeSH
• protinádorové látky farmakologie   terapeutické užití   MeSH
• regulace genové exprese u nádorů účinky léků   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Disruption of microtubules has been shown to cause suppression of inducibility of major cytochromes P450 (CYP) through several nuclear receptors. Here we tested the effects of structurally different clinically used microtubules-interfering agents (MIAs), such as colchicine, vincristine, vinblastine, nocodazole and taxol on aryl hydrocarbon receptor signaling pathway in human hepatocytes. We show that tested MIAs inhibit 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible expression of CYP1A2 mRNA and restrict TCDD-dependent nuclear translocation of aryl hydrocarbon receptor. On the other hand, these MIAs increased the content of aryl hydrocarbon receptor protein and mRNA by transcriptional mechanism. We show that the MIAs activate c-Jun -N-terminal kinase (JNK), partly p38 but not extracellular-regulated protein kinase (ERK). Consistently, sorbitol, a model activator of JNK, inhibited TCDD-mediated induction of CYP1A2 mRNA and down-regulated tyrosine aminotransferase mRNA - a target gene of glucocorticoid receptor. Dexamethasone had the opposite effect on aryl hydrocarbon receptor signaling and decreased aryl hydrocarbon receptor mRNA and augmented the inducibility of CYP1A2 by TCDD. We conclude that the effects of tested MIAs on aryl hydrocarbon receptor-CYP1A2 signaling pathway are dual, i.e. they inhibit transcriptional activity and nuclear translocation of aryl hydrocarbon receptor but in parallel increase aryl hydrocarbon receptor protein and mRNA level. Microtubules destabilizers have the same effects as stabilizer taxol. This implies that aryl hydrocarbon receptor functions depend on microtubules dynamics but not integrity. Perturbation of aryl hydrocarbon receptor-CYP1A2 signaling by MIAs comprises glucocorticoid receptor-JNK and probably aryl hydrocarbon receptor-JNK/glucocorticoid receptor interactions. We also demonstrate that the effects of MIAs in human hepatocytes do not proceed via arresting cell cycle as confirmed by flow cytometry (FACS) analyses.

• MeSH
• buněčný cyklus účinky léků   MeSH
• cytochrom P-450 CYP1A2 metabolismus   účinky léků   MeSH
• financování organizované MeSH
• hepatocyty metabolismus   účinky léků   MeSH
• JNK mitogenem aktivované proteinkinasy metabolismus   účinky léků   MeSH
• kultivované buňky MeSH
• lidé MeSH
• messenger RNA metabolismus   MeSH
• mikrotubuly metabolismus   účinky léků   MeSH
• modulátory tubulinu farmakologie   MeSH
• průtoková cytometrie MeSH
• receptory aromatických uhlovodíků metabolismus   účinky léků   MeSH
• receptory glukokortikoidů metabolismus   účinky léků   MeSH
• regulace genové exprese enzymů účinky léků   MeSH
• signální transdukce MeSH
• Check Tag
• lidé MeSH

Cellular signaling by glucocorticoid receptor and aryl hydrocarbon receptor is restricted by microtubules interfering agents (MIAs). This leads to down-regulation of drug metabolizing enzymes and drug interactions. Here we investigated the effects of all-trans-retinoic acid (ATRA) and MIAs, i.e. colchicine, nocodazole and taxol on the regulation of retinoic acid receptor (RAR) genes in primary cultures of rat hepatocytes. ATRA (1microM) down-regulated RARalpha and RARgamma mRNAs (decrease 23% and 41%, respectively) whereas it up-regulated RARbeta mRNA (4.3-fold induction). All MIAs diminished the expression of RARs in dose-dependent manner; the potency of MIAs increased in order NOC

• MeSH
• financování organizované MeSH
• genetická transkripce účinky záření   MeSH
• HeLa buňky cytologie   metabolismus   účinky léků   MeSH
• inhibitory proteasomu MeSH
• katalýza účinky léků   MeSH
• kolchicin farmakologie   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• leupeptiny farmakologie   MeSH
• lidé MeSH
• messenger RNA genetika   metabolismus   MeSH
• mikrotubuly účinky léků   MeSH
• modulátory tubulinu farmakologie   MeSH
• proteasomový endopeptidasový komplex MeSH
• receptory kyseliny retinové genetika   metabolismus   MeSH
• regulace genové exprese účinky záření   MeSH
• termodynamika MeSH
• transglutaminasy metabolismus   MeSH
• tretinoin farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH

Molekulárně cílená léčba poskytuje nemocným s nemalobuněčným plicním karcinomem významnou šanci na prodloužení života a zlepšení jeho kvality. Od roku 2004 jsou shromažďovány důkazy o účinnosti inhibitorů tyrosinkinázy EGFR u nádorů obsahujících tzv. senzitivní mutace. V posledních letech jsme svědky objevování dalších, tzv. řídících mutací a hledání molekul využitelných v cílené léčbě nádorů závislých na definovaných onkogenech. Karcinomy plic zůstávají závažnou medicínskou i společenskou problematikou. V České republice jsme i při vysokém podílu chirurgicky neléčitelných nemocných svědky pozvolného prodlužování života i zlepšování jeho kvality, také díky chemoterapii orientované podle histologického nálezu a molekulárně cílené léčbě. Crizotinib je nový lék s prokazatelnou účinností u podskupiny nemocných s nemalobuněčným plicním karcinomem s translokací genu EML4-ALK. Předložená práce shrnuje základní teoretické údaje z oblasti přestavby genu ALK, diagnostické postupy pro průkaz translokace genu ALK, farmakologické údaje týkající se crizotinibu, dosavadní výsledky klinických studií a klinické zkušenosti s tímto lékem. V současné době se diagnostika přestavby genu ALK provádí na vybraných pracovištích specializovanými patology. Crizotinib se podává nemocným s průkazem translokace EML4-ALK zatím v rámci programu časného přístupu, ve 2. nebo 3. linii terapie. Lék je obvykle velmi dobře snášen. V průběhu léčby může dojít k relapsu onemocnění, jehož příčinou mohou být rezistentní mutace EML4-ALK nebo vznik mutací jiných genů. Účinnost crizotinibu je v současnosti předmětem výzkumu i u karcinomů plic s jinými řídícími genetickými změnami, jako jsou amplifikace genu c-Met a přestavba genu ROS1.

Targeted molecular therapy provides a significant chance to patients with non- -small-cell lung cancer, extending their life and improving its quality. Since 2004 evidence has accumulated confirming the efficacy of EGFR tyrosine kinase inhibitors in tumours with so-called sensitive mutations. Over last years we are witnessing a series of discoveries of other, so-called controlling mutations and the search for molecules that could be used for targeted treatment of tumours dependent on defined oncogenes. Lung cancers remain a grave medical and societal problem. In the Czech Republic we have seen, in spite of a high proportion of patients who cannot be treated surgically, gradually extending patient survival as well as improving quality of life, partly due to chemotherapy respecting histological findings, but also due to targeted molecular therapy. Crizotinib is a new drug with demonstrated efficacy in the subgroup of patients with non-small-cell lung cancer with EML4-ALK gene translocation. The present work summarizes basic theoretical data on ALK gene transformation, diagnostic procedures used to demonstrate ALK gene translocation, pharmacological data concerning crizotinib, clinical trial results obtained so far and clinical experience with this drug. The diagnostics of ALK gene transformation is currently conducted by specialized pathologists in selected institutions. Crizotinib is administered to patients with demonstrated EML4-ALK translocation as part of an early access programme, as second- or third line therapy. Toleration of the drug is usually very good. Over the course of treatment relapse of the disease may occur that can be caused by resistant EML4-ALK mutations or newly formed mutation of other genes. The efficacy of crizotinib is currently being investigated also in lung cancers with other controlling genetic changes, such as c-Met gene amplification and ROS1 gene transformation.

• MeSH
• chemorezistence MeSH
• cílená molekulární terapie * metody   využití   MeSH
• hodnocení léčiv MeSH
• hybridizace in situ fluorescenční MeSH
• imunohistochemie MeSH
• inhibitory proteinkinas * aplikace a dávkování   farmakokinetika   farmakologie   škodlivé účinky   terapeutické užití   MeSH
• klinické zkoušky, fáze I jako téma MeSH
• klinické zkoušky, fáze II jako téma MeSH
• klinické zkoušky, fáze III jako téma MeSH
• kombinovaná farmakoterapie MeSH
• lékové interakce MeSH
• lidé MeSH
• nemalobuněčný karcinom plic * farmakoterapie   MeSH
• polymerázová řetězová reakce MeSH
• proteiny asociované s mikrotubuly MeSH
• protinádorové látky aplikace a dávkování   farmakokinetika   terapeutické užití   MeSH
• pyrazoly terapeutické užití   MeSH
• pyridiny terapeutické užití   MeSH
• translokace genetická MeSH
• Check Tag
• lidé MeSH

Prostate cancer is primarily fatal after it becomes metastatic and castration-resistant despite novel combined hormonal and chemotherapeutic regimens. Hence, new therapeutic concepts and drug delivery strategies are urgently needed for the eradication of this devastating disease. Here we report the highly specific, in situ click chemistry driven pretargeted delivery of cytotoxic drug carriers to PSMA(+) prostate cancer cells. Anti-PSMA 5D3 mAb and its F(ab')2 fragments were functionalized with trans-cyclooctene (TCO), labeled with a fluorophore, and used as pretargeting components. Human serum albumin (ALB) was loaded with the DM1 antitubulin agent, functionalized with PEGylated tetrazine (PEG4-Tz), labeled with a fluorophore, and used as the drug delivery component. The internalization kinetics of components and the therapeutic efficacy of the pretargeted click therapy were studied in PSMA(+) PC3-PIP and PSMA(-) PC3-Flu control cells. The F(ab')2 fragments were internalized faster than 5D3 mAb in PSMA(+) PC3-PIP cells. In the two-component pretargeted imaging study, both components were colocalized in a perinuclear location of the cytoplasm of PC3-PIP cells. Better colocalization was achieved when 5D3 mAb was used as the pretargeting component. Consecutively, the in vitro cell viability study shows a significantly higher therapeutic effect of click therapy in PC3-PIP cells when 5D3 mAb was used for pretargeting, compared to its F(ab')2 derivative. 5D3 mAb has a longer lifetime on the cell surface, when compared to its F(ab')2 analogue, enabling efficient cross-linking with the drug delivery component and increased efficacy. Pretargeting and drug delivery components were cross-linked via multiple bioorthogonal click chemistry reactions on the surface of PSMA(+) PC cells forming nanoclusters, which undergo fast cellular internalization and intracellular transport to perinuclear locations.

• MeSH
• albuminy MeSH
• antigeny povrchové imunologie   MeSH
• click chemie metody   MeSH
• cyklooktany chemie   MeSH
• fluorbenzeny chemie   MeSH
• fytogenní protinádorové látky terapeutické užití   MeSH
• glutamátkarboxypeptidasa II imunologie   metabolismus   MeSH
• imunoglobuliny - Fab fragmenty chemie   metabolismus   terapeutické užití   MeSH
• lékové transportní systémy metody   MeSH
• lidé MeSH
• maytansin terapeutické užití   MeSH
• modulátory tubulinu terapeutické užití   MeSH
• monoklonální protilátky chemie   metabolismus   terapeutické užití   MeSH
• nádorové buněčné linie MeSH
• nádory prostaty farmakoterapie   enzymologie   metabolismus   MeSH
• nanomedicína MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

The taxanes that target microtubules are among the most active drugs in breast cancer treatment; however, resistance to these agents remains a significant issue for many patients. The epothilones are a novel class of nontaxane, microtubule-targeting agents, currently being evaluated in varying stages of clinical trials. Ixabepilone is the first epothilone analogue to receive US Food and Drug Administration approval in the United States for the treatment of metastatic breast cancer and as such will be the primary focus of this review. RECENT FINDINGS: Multiple phase II trials evaluating ixabepilone in different populations of patients with metastatic breast cancer as well as a phase III trial in combination with capecitabine have recently been published. SUMMARY: Phase II trials clearly demonstrate the activity of single-agent ixabepilone in both taxane-untreated and taxane-treated metastatic breast cancer. Although the highest activity was seen in early lines of therapy, there was also clear evidence of activity in heavily pretreated patients. Ixabepilone has also been evaluated in combination with capecitabine in a randomized, phase III trial demonstrating a benefit for the combination compared with single-agent capecitabine for patients resistant to anthracyclines and taxanes. In general, ixabepilone administered as a single-agent and in combination with capecitabine has been reasonably well tolerated.

• MeSH
• deoxycytidin analogy a deriváty   terapeutické užití   MeSH
• epothilony terapeutické užití   MeSH
• fluoruracil analogy a deriváty   terapeutické užití   MeSH
• klinické zkoušky jako téma MeSH
• lidé MeSH
• metastázy nádorů MeSH
• mikrotubuly metabolismus   MeSH
• modulátory tubulinu MeSH
• nádory prsu farmakoterapie   patologie   MeSH
• protinádorové látky terapeutické užití   MeSH
• randomizované kontrolované studie jako téma MeSH
• taxoidy chemie   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH